Driving-chain for transmitting power.



(I-1H. DOUGLAS.

DRlVlNG CHAIN FOR TRANSMITTING POWER.

APPLICATION FILED NOV. 15; 1913.

1 Patented June 1, 1915.

I WITNESSES:

9M aw MW $21M 4g .not confined to any strict con CHARLES H. DOUGLAS, OFSPRINGFIELD, MASSACHUSETTS, ASSIGNOR TO DOUGLAS SAW & MACHINERY 00., 0FBOSTON, MASSACHUSETTS.

.DRIVING-CHAIN FOR TRANSMITTING POWER.

Specification of Letters Patent.

Patented June 1, 1915.

To'all whom it may concern:

Be it known that I, CHARLES H. DOUGLAS,

a citizen of the United States, residing at Springfield, in the countyof Hampden and State of Massachusetts, have invented certain new anduseful Improvements in Driving-Chains for Transmitting Power, of whichthe following is a specification.

This invention has reference to improvements in driving chains fortransmitting power and particularly in driving chains of the silenttype.

The object of the present invention is to produce a driving chain thatwill run silently at a much higher linear speed than driving chains nowin use, and the chain of the present invention is designed particularlyfor'driving circular saws for cutting timber.

Heretofore driving chains have been proposed for use in connection withgear wheels to provide a non-slipping positive drive not at alldependent upon friction, but such dri chains because of theirconstruction are ent only .at relatively low linear speeds, say, fromseven hundred to a thousand feet per minute, but when relatively highspeeds, say, two thousandv or more feet per minute, are demanded, as inthe case of circular saws, the noise produced is obtrusive, this beingdue to the rapid impact of the links of the chain with the gear wheelthus subjecting the chain to a great multitude of shocks which in acomparatively short time act destructivelyupon the chain.

In accordance with the present invention the chain is so made that itengages the gear wheel without shock and the links make ure a slidingaction. Moreover, in accord-' ance with the present invention wear inthe chain is readily compensated for so that in the event of the chainbecoming loose with relation to the gear wheels because of wear the gearwheels themselves may be effectively enlarged to take up all wear.

The invention will be best understood from a consideration ofthefollowing detailed description, taken-in connection with theaccompanying drawings forming a part of this specification with thefurther understanding that While the drawings show a practical form ofthe invention the latter is formity with the showing of the drawings,but may be changed and modified so long as such changes andmodifications mark no materlal departure from the salient features ofthe invention.

In the drawings :Figure 1 is a side elevation of a part of a gear wheelshowing a portion of the improved chain applied thereto, with some partsin section. Fig. 2 is a section on the line az-w of Fig. 1. Fig. 3 is aplan view of a portion of the chain as seen from the face that engagesthe Wheel. Fig. 4 is a fragmentary longitudinal section through thechain with a corresponding portion of the gear Wheel in elevation.

In the drawings there is shown a chain A and a portion of a gear wheelB. The chain is made up of links a and other links 6, and the links areheld together by pins or rivets 9 upon which the links may rock freely,yet are arranged to fit s0 snugly that there is no appreciable lostmotion.

The links a are arranged at the sides of the chain and'may either bestraight or nearly so, the links a being shown in Fig. 1 as slightlycurved with their long sides concentric with the center of the wheel B,which latter may be taken as the largest wheel to which the chain isapplied, and the links a because of their oifice may be termedsupporting or "carrying links for the chain, as will hereinafter appear.In chains of medium width there is provided a series of links a at themargins or edges only, while in the wider form of chains an intermediateseries of links a may be employed. The other links I) of the chain areshown as each provided with rounded ends a concentric with thelongitudinal axis of the respective pins or rivets g and in one longedge of each link I) there is formed a recess d intermediate of therounded ends a.

The gear wheel B is, formed with teethon opposite sides of theintermediate ledge 11o h and terminating at the outer ledges h. Thechain, however, is of the full width of the wheel including the outerledges 72., while the links I) are confined to those portions of thechain which conform to the teeth f, and in the absence of theintermediate ledge h thev links I; occupy all of the width of the chainwith the exception of the outer supporting links a.

In the event of wear of the links there are provided bushing rings D soarranged that the outer surface of each ring is of slightly greaterdiameter than the throat portions of the wheel B between the teeth f.For me-' chanical reasons the bushing ring D must be made of anappreciable thickness of metal, say, a quarter of an inch, more or less,while the amount of wear of the chain to be taken up may represent but asmall fraction of an inch, say, a hundredth of an inch, more or less. Toapply the rings D the side or marginal shouldershare appropriatelyreduced in diameter, and then the rings D are fitted and their externaldiameter is made appropriately large to compensate for the wear.

The external diameter of the shoulders or ledges h, or in'the case ofthe presence of the bushing rings D, the external diameter of the latteris such at all times that when the links a engage the wheel B the links6 where their rounded ends 0 would otherwise engage the wheel at thethroats between the teeth ,1 and where the outer ends of the said teethwould otherwise engage the bottoms of the notches d, there is left asmall space which may be but a small fraction of an inch, say, ahundredth of an inch, more or less, wherefore there can be no impactbetween the links I) and the bottoms of'the throats between the gearteeth f or between the outer ends of the latter and the bottoms of therecesses 03, while the rounded ends of the links I) engage the teeth fbya combined rolling and sliding. action.

The links a come gradually to rest upon the smooth ledges or shouldersprovided for their reception, whether these ledges or shoulders berepresented by the body of the wheel or by the outer surfaces of therings D and the links a if made to conform to such shoulders or ledgescome to rest thereupon smoothly and. gently. If the links a be curvedinto conformity with the curvature of the smooth ledges or shoulders ofthe largest wheel to which the chain is applied, then when passing abouta smaller wheel only the central or intermediate portions ofthese linksengage the smooth shoulders or ledges, and any tendency to come intosudden engagement with the gear wheels and so roduce a noise isminimized by the extreme y small area of contact limited tosubstantially the center portion of the link. There is no blow or impactimter make engagement with the links between the rounded ends thereof.The slight spacing of the power links away from the wheel or outer edgesof the teeth, which spacing is shown in Fig. 4, but is not necessarilyso great as therein indicated, prevents bottoming of the links withrespect to the wheel, and this is due to the presence of the inactivesupporting links a engaging circumferentially smooth portions of thewheel represented by the ledges h, or in the presence of the bushingrings D, the outer surfaces of the latter.

What is claimed is 1. In a power drive chain structure, the combinationwith a wheel having driving teeth and unyielding circumferentiallysmooth peripheral surfaces at the sides of the teeth, of a driving chainprovided with driving links for meshing with the driving teeth of thewheel, and-other links shaped to coiiperate with the smooth surfaces ofthe gear wheel the position of the smooth surfaces with respect to thethroats between the teeth and the relation of the second-named links tothe first-named links and to the smooth surfaces being such as to holdthe drivin links from bottoming engagement with t e throats between theteeth.

2. A chain drive comprising a gear wheel having rigid or unyieldingshoulders or ledges at the sides of the teeth, and a chain having linkswith ends shaped to engage the havin edge portions adapted to ride onthe shoul ers or ledges at the sides of the teeth,

the diameter of the shouldersor ledges with respect to the throatsbetween the teeth and the radial position of the second-named links withrespect to the first-named links being such as to hold the first-namedlinks from bottoming engagement with the throats between the teeth andthe outer ends of the teeth from bottoming in the recesses of saidlinks. v v

3. In a chain drive, the combination of a chain composed of active orpower links and other supportin links for the ower links, and a gearwhee having teeth or engaging the power links and providedvwith rigid orunyielding means for the su porting constructed and arranged withrespect to said supporting links so as to prevent the power links fromforcibly striking the gear wheel between the teeth thereof.

4. In achain drive, the combination with a chain composed of active orpower links.

ing links, said ledges being in the form of ri 'd or un ieldin rin s alied to the geg r wheel, and i'bmov ble therefrom to give place to likerings of greater external iameter to compensate for stretch of the drivechain, and said ledges and supporting links being related to prevent thepower links from forcibly striking the gear wheel between the teeththereof.

5. In a chain drive, a chain composed of active or power links and otherlinks eonstituting links, gaging the power links and'rigid or unyieldingperipheral ledges for receiving the supporting links, the ledges beingof greater radial distance from the axis of the gear wheel than thebottoms of the throats between the teeth of the gear wheel, whereby thesupporting links prevent the ower links from striking the bottoms of saithroats.

In testimony whereof I have aflixed my signature in presence of twowitnesses.

CHARLES H. DOUGLAS. Witnesses:

JOHN H. Smonns, Enrrrr L. BROWN.

supporting links for the power and a gear wheel having teeth for en-

